Amino acid imbalance and tryptophanniacin metabolism: I. Effect of excess leucine on the urinary excretion of tryptophan-niacin metabolites in rats

The effect of feeding excess leucine on the urinary excretion of tryptophan-niacin metabolites and nitrogen was studied in young and adult rats. Urinary excretion of quinolinic acid and N'methylnicotinamide was increased in both young and adult rats when L-leucine was added at 1.5% level to a 9% casein diet. Quinolinic acid excretion was more markedly affected in young rats, whereas N'-methylnicotinamide excretion was more affected in adult rats. Isoleucine counteracted the effect of leucine in young rats. Nitrogen excretion increased on leucine feeding in adult rats but not in young rats. Adult rats fed a jowar (Sorghum vulgare) diet tended to excrete relatively more N'-methylnicotinamide and niacin than when fed a wheat diet

Pattern of nicotinamide nucleotides in the erythrocytes of pellagrins

Nicotinamide nucleotides in the erythrocytes of normal human subjects and of patients suffering from pellagra were separated by paper chromatography and their concentrations determined. Though no differences were observed in the concentration of total nicotinamide nucleotides in erythrocytes of pellagrins and normals, significant differences were observed with regard to concentration of the individual nucleotides. The erythrocytes of pellagrins had significantly higher amounts of NMN than the erythrocytes of normal subjects, while levels of NAD and NADP tended to be lower in the pellagrins as compared to normals

Bioactive phytochemicals with emphasis on dietary practices

Diet can modify the pathophysiological processes of various metabolic disorders and can be an effective preventive strategy for various disease processes most of which are known to involve oxidative damage. Both nutrient and non-nutrient components of the diet have been recognized for their anti-oxidant and other potential benefits. Plant foods contain phytochemicals such as flavonoids, phenolic acids, etc., which show biological activity. Some common foods used in Indian culinary practices were assessed for their anti-oxidant, anti-mutagenic and anti-carcinogenic effects and vitamin D activity and evaluated for their plausible biological effects. Green leafy vegetables had the highest anti-oxidant activity followed by wheat and rice. Cooking decreased this activity. Eugenol, the active principle of clove, was shown to offer protection against CCl4 induced hepatotoxicity in rats. It also showed anti-peroxidative activity in addition to decrease in O2 formation. Studies on the anti-carcinogenic effect of turmeric/curcumin revealed that both are potent anti-mutagens in vivo and reduce the adducted DNA levels in liver of rates challenged with B(a)P. In another study, Syrian hamsters receiving turmeric/curcumin through diet or local paint on cheek pouch had lower tumour burden as well as adducted DNA level against 7-12-DMBA challenge. Turmeric/curcumin were found to be better anti-tumour agents when given in the post initiation phase of carcinogenesis. The beneficial effect of turmeric was found to be due to its anti-oxidant potential. Studies on humans at risk of palatal cancer due to reverse smoking showed that turmeric (1 g/day) for 9 months had a significant impact on the regression of precancerous lesions. Onion and garlic also possess anti-mutagenic principle. Further studies on the bioactive phytochemicals in plants showed that certain plants belonging to Solanaceae (Cestrum diurnum, Lycopersicon esculentum and Solanum melongena) have calcinogenic potential and vitamin D like activity. In view of the vast data on bioactive principles from plants, it is suggested that dietary prevention coupled with other life-style changes in perhaps the right answer for prevention of cancer and other chronic diseases in India